The present invention relates to the renting ot computerized means (software and/or hardware) in accordance with a schedule which depends on the actual use of this facility.
This schedule can be compiled on the basis of various measures such as the period for which a piece of software is made available, the duration of use of this piece of software, the number of transactions made or dossiers created, the number and quality (difficulty or rarity) of calculations, the number and quality of files consulted, especially, and more generally of any computing or remote-computing service made available to a user, and the operation of which is enabled at least in part by the said software.
A fair number of proposals have already been made for providing protection for the supplier (or designer) of a piece of software, especially: EP-A-0,430,734; IEICE transactions, vol. E 73, No. 7, July 1990, JP, pp 1133-1146; EP-A-0,265,183.
Thus, the concept is known of a computerized device, of the type including:
an operational facility, comprising at least one central processing unit, together with memory means allowing it to load an operating system and to implement at least one piece of software on the basis of this operating system, and together with at least one connection interface which can be accessed through a function of the operating system, and PA1 a dedicated unit including a removable memory medium reader, such as a smart-card reader, connected to the central processing unit by the said connection interface of the latter, PA1 while the software includes specific calls to the dedicated unit, for the purposes of conditioning the conduct of the execution of the said software, depending on the state of certain data contained in the removable memory medium. PA1 a communication security module capable of disabling the response to a communication command originating from the central processing unit, depending on first conditions involving the expression of the communication command, and information contained in the card, and PA1 at least one responsive module capable of recognizing such a communication command and of according it a favourable response, in the said particular form, only if second conditions pertaining to the arguments of the said command and to information contained in the card are complied with.
This is done in EP-A-0 430 734, with the intention of the software sending results to the smart card which it will have to be able to retrieve therefrom subsequently, failing which the software cannot be fully executed.
These known solutions are not entirely satisfactory from the security standpoint, it being observed that a perfect security system is inconceivable.